Drill



Aug. 24 1926.

A. F. MELCHER DRILL Filed May 25 192:5

Patented 'g. 24, 1926.

UNITED STATES PATENT oFFl/CE.

' DRILL.

Application med May 25, 1923. Serial No. 641,45-9.

My invention relates to an improvement in drills for extracting cores or samples from wells or drillings for the urpose of scientific study and practical examination. For convenience I will limit the discussion herein toits use in the drilling of oily wells, although it is, of course, understood that my invention is not thus limited and extends to all ofthe fields in which it can be used.

A common system of drilling oil wells isthe churn drill system. A solid drill is suspended froth-'a steel cable which passes over awalkin'g beam to a reel. A vertical reciprocating motion is imparted tothe cable by the walking beam and the drill is thus alternately lifted and then dropped, the length of the cable being so adjusted that the drill strikes the earth on each downward stroke. The system is eiiicient-in cutting a hole through the rock, but the cuttings are.

pulverized or so finely divided that they are of littlewalue for the purpose of study to` determine the geologic and physical characteristics of the strata` through which the drill is passing. Sincev the characterof these strata is one of the most important guides to the driller for estimating the robability of, `striking oil and the pro able f quantityof itwhen found, it is essential for him to obtain unbroken samples of sufficient size for proper examination. It is equally important for him to lmow positively that the samples have vcome from the bottom of the hole and are not sim ly fragments which have fallen from lthe sides of the hole tothe bottom-a fact of which he can never ibe* certain when relying upon the cuttings of I Y the churn drill.

limited extent for obtaining samples of the "f strata, but this custom has not prevailed in the oil fields iprobably because of the great cost of such drills.

The object of my invention 'is to provide interior of the drill.

an eiiicient and inexpensive drill for obtaining samples without otherwise altering the customary drilling methods. As I have said, its use is not limited to oil drilling.

Broadly stated, m invention is a drill with a chambered bo y provided with means 'for retaining the core within the drill. The

device also includes means whereby the re taining elementmay be automatically maintained in free operable condition.' Only one embodiment is illustrated by the accompany ing drawings, in which- Figure 1 is a side elevationof the drill; Figure 2 is a longitudinal section, and Figure 3 an end view of the cutting end. The drill consists of a body 1, terminating in a shank 2 at its upper end by which it is attached to the cable. At its lower end is provided a chamber 4, and adjacent there-- to is the drilling face having cutters 3. An opening 5 in the upper end of the interior chamber 4 communicates with the exterior` of the drill by a passage-way 6, which may or may'not be closed by a flap of leather or other suitable material 7. -In the body of the drill are also formed one or more aper' tures or chambers 8 which communicate with the interior and exterior of the drill, as shown and each of these chambers is ada ted to receive a dog 9 having downwardly projecting leg 10, which acts as a loose hinge for the dog, and an arm 11 which normally projects through the rpening 12 into the e exterior o ening Partially close by a brass or other suitoi the chamber 8 is tubular bushin 13 o able material w ich serves as the outer wall of the chamber within which the dog 9 is loosely retained and at the same time affords a more or less restricted passage between the exterior and'intergior of the drill. The interior of thebody may be counterbored as at 14 and 15, so that the interior diameter of these portions is larger than the interior diameter of the lower portionl. On the exterior surface of the drill are formed two diametrically opposed depressions 17, commonly called water courses.

. The operation of the device herein described is as follows:

When it is desired to obtain a sample of the strata at the bottom of a hole, the ordinary drill is removed from the endof the cable and my drill substituted therefor. It is then lowered to the bottom of the hole and core and cause it to be retained in the corey chamber after it has been broken o' by the concussion of the down stroke of the drill. It may happen that the core will not .be broken od when the dog first engages with it. In that case the dog will be pulled loose from the core on the next up stroke of the drill to engage again on the following de- -secending stroke. And practice has demonstrated that the core will be certain to break 0E from the bottom of the hole because of the concussion and vibration of the -drill before it has attained a height equal to that of the interior chamber ol the drill. When this occursthe dog will function to retaln the core within the drill. Sincethe first sample vmay'not be satisfactorytit 1s customary to continue drilling until samples are obtained which approximately fill the interior of the drill. Each of these samples is obtained as above described. Iheir retention in the body of the drill is facilitated by the counterbored portions 111 and 15, into which the first sample, broken od, is lifted by succeeding samples, and where it tends to jam because of the smaller diameter of the lowest section 16 of the drill interior.

To lubricate the drill it is customary to pour water'into the drill hole unless sulficient moisture from natural sources 1s present. As the drill descends it is necessary to provide for the escape of the moisture and drillings which are technically called slush. In the ordinary drill, escape of the slush is provided for by means of depressions in the sides of the body of the drill similar to that shown at 17, but ordinarily deeper. As the drill descends the slush passes upward through these courses to return downwardly again as the drill ascends. In my invention I lprefer to have the water courses relatively shallow so that the "passage of the slush through them is quiterestricted, with the result that a certain proportion of slush will be forced up through the interior of the drill and out to the exterior through the. opening 12 and the chamber 8 and the opening 18 thus keeping the chamber '8 free from obstructions to insure-free operation of the dog.

The loose mounting of the dog also assists in this function. While the dog may be said to swing on its lower end as a hinge, it will be noted that the so-called hinge is `bottom of the chamber.

memes formed merely by the leg of the dog resting on the bottom of the chamber 8 and that this point of contact may be at any part of the It will also be seen that the opening 12 of the chamber 8 is somewhat larger than necessary for the accommodation of the gripping end of the dog which not only provides an outlet for slush through the chamber 8 and its external opening 1 8, but' permits the lower end ofthe dog to lift entirely 0H the bottom of the chamber 8. In-other words, the dog can oscillate to a limited extent in a vertical, as well as a horizontal direction and thus act as an agitator to prevent the settling of solid matter in the chamber.

. The passage-way 6 through which the interior of the tool communicates with the exterior .at its upper end, affords an exitfor any slush which is unable toescape by the means already described, and enables it to assist in lifting the sample intothe upper part of the interior of the drill. On the upward stroke of the drill the slush Hows in the opposite direction, acertain amount passing inwardly through the chamber 8, thus assistingv in 'forcing thegdogs towards the interior of the drill, and at the same time removing any 'sediment which may have accumulated in the chamber 8. 'The check valve 7 may be added if desired to close the passage 6 on the up-stroke of the drill.

When my drill is to be usedin drilling by the rotary system in which `the drill is given a rotary motion by a tubular shaft extending to the surface, the passage-way 6 maybe omitted since in such drills there is customarily a passage through the shank of the drill communicating'with the tubular shaft through which the necessary lubricating moist-ure` may be conveyed to the cutting edge of the drill. The motion of the drill is rotary and not reciprocating as in the case of the churn drill, and, therefore, no passage-'way` such; as 6 is required since there is no necessity of relieving internal pressure.

No other material change is necessary, myl improved drill being substituted for the regular rotary drill whenever it is desiredv to obtain a sample.

Having thus described -an embodiment of the invention, what I claim is: 1. A core drill having walll pockets provided with apertures communicating with the interiorA and exterior of the drill, and

4core-gripping and retaining means looseetv communication between the exterior and 4. A drill having a hollow body with interior of the drill and thereby maintain pockets within the side walls thereof, each the dogs in operable condition. pocket having a depression, a dog in each 10 3. A drill having a hollow body, pockets pocket seated in the depression and capable 5 in the side Walls thereof and dogs seated of limited movement in all directions.

within said pockets capable of limited movement in all directions. ARLES FRANCIS MELCHER. 

